Time flies and once again
an age has passed without me updating my website. It just seems
there is so much to do that documenting any of it take second place!

MetaSwitch continues to
march across the world, (recently boosted by a funding deal with
Francisco Partners,) and I continue to play a key architectural role in
ensuring it can meet future challenges as well or better than it has met
past ones.

My art work with Paul also
continues to go from strength to strength and we're currently working on
a large show in London in October. As before my focus is mainly,
but not exclusively, on the engineering and science side, and this time
includes not only vacuum and high voltage work, but also the production
of some multi-ton, fine machined metal sculptures (exactly what they are
will have to remain secret until the show opens ;-).

What else to say?

Personally one of the most interesting things which has
come up recently is a question of "classification".
With various press-releases and books related to the art work, I'm
frequently asked how I want to be described: "Artist", "Scientist",
"Physicist", "Engineer"?

As should be obvious from
my previous writings I'm against such narrow boxing in of what I or
others, do or think. I strongly feel it restricts people's view of
what they or others are capable, and depending on circumstance I'll view
the world from all of the above perspectives, sometimes several at once.

Having said that, if
I was really pushed, I suspect I would have to go with Engineer. Yes I
formally trained as a physicist, and yes science gives me a unifying
framework within which to understand and investigate the world.
However, ultimately, I want to do more than understand the world - I
want to go out and build things which change it, and allow us to do
things which wouldn't otherwise be possible. If that doesn't make
me an engineer, I don't know what does.

Where does that desire come
from? That's hard to pin down precisely, but there are a number of
likely candidates.

I grew up with a father who
was a jig and tool designer at W.H. Allens, (a medium to heavy
engineering firm that built large diesel engines, steam turbines and the
like,) and from my earliest age remember being fascinated by what
he did. The yearly visits to "the works" left a particular
impression on a little lad. Going round the shop floor there were
huge machines for machining parts of multi-MW turbines or engines,
ultra-sensitive measuring stations what could quantify micron level
surface roughness and massive heat-treatment furnaces belching out heat
when the doors opened. But most particularly I remember being
allowed to step inside the crankcase of one of the large diesel
engines prior to final assembly.

At home this engagement with engineering continued.
Lego was the starting point, but before long I was "helping" take apart
and later put back together car engines. And I still remember the
day I was first allowed to use the Atlas lathe which my father had in
the garage. Taking a raw chunk of metal and shaping it into
something precisely the shape you wanted was (and still is) amazing.

The one other things which really sticks in my mind
while growing up was a BBC TV children's TV program. I can't
remember the presenter, but the title music was "The Montagues &
Capulets" from Prokofiev's Romeo & Juliet, and it was all about great
engineers: Brunel, Watt, Stephenson, etc. The program just left me
enthralled to the idea of making things which could change the world and
I have never lost the love.

Interestingly, I know of at least three other people who
were similarly entranced by that program and have gone on to be
engineers of one form or another.

Sadly such programs now seem few and far between, but if
anything this just increases my desire to pass on the torch to a younger
generation...

Update (23 March 2006)

"A good many times I have been present at
gatherings of people who, by the standards of the traditional culture,
are thought highly educated and who have with considerable gusto been
expressing their incredulity of scientists. Once or twice I have been
provoked and have asked the company how many of them could describe the
Second Law of Thermodynamics. The response was cold: it was also
negative. Yet I was asking something which is the scientific equivalent
of: Have you read a work of Shakespeare's?

I now believe that if I had asked an even simpler
question -- such as, What do you mean by mass, or acceleration, which is
the scientific equivalent of saying, Can you read? -- not more
than one in ten of the highly educated would have felt that I was
speaking the same language. So the great edifice of modern physics goes
up, and the majority of the cleverest people in the western world have
about as much insight into it as their neolithic ancestors would have
had."

C.P. Snow

It's a long time since I've done any serious work on my
website, but I can only look on this as a good thing, reflecting the fact
that I've not had an idle moment. Even now I have time for no more
than a quick update.

At "work" I've helped take my company http://www.dataconnection.com,
from straight software, into the world of next generation telecoms http://www.metaswitch.com.
This has required us to progress for a smallish company supplying cutting
edge software technology to a range of people from small startups to the
major player (Cisco, IBM, Microsoft. Lucent, HP, Nortel, etc.) to a
much larger company, who in addition to what we did before, is now shaping
the world of next generation telecommunication.

At "home", my partner and I have emigrated from
London to Hampshire and the New Forest. A huge change of lifestyle,
but one that seems so far to be working out well, with free open spaces
and a range of different landscapes never more than a minute away.

Through all this, however, I've maintained my passion for
the beauty and wonder present in the everyday world, both readily apparent
and also hidden unless viewed with the aid of Science.
Deepening this vision was what drove me to study theoretical physics at
Cambridge (and to build some of the "toys" documented below),
and is the same thing that makes me want to fight against the "Two
Cultures" so accurately (and painfully) captured by C.P.
Snow.

In both the arts and sciences, some areas &
disciplines are easier to access and appreciate than others; both are
often taught very dryly in schools, and both have their esoteric areas
where few will ever venture. Having said that, it is in many ways easier
for the uninitiated to get drawn into the arts. It might take a life
time of study to appreciate the full complexity of a Shakespeare tragedy,
a Mozart sonata or Michelangelo's David, but for most people, even on the
first exposure, there will be at degree of resonance. If not, then
there is a world of other artists and pieces out there fighting to inspire
interest.

With the sciences things are different. Many of the
world's great wonders go overlooked, reduced to mere technologies
contained in everyday devices. Viewed in the right way fabulous
things can still be seen, but the degree of instant engagement is often
similar to that of a great musical work perverted into the muzak you hear
in a lift.

This is not only sad, but is also dangerous. Unless people
have a basic understanding of how the world works, and unless they learn
how to weigh evidence and apply Occam's Razor, they leave themselves (in
this increasingly technological world) at the mercy of others.
Humanity as a whole is facing some critical challenges and people need to
be able to make sound judgments for themselves, not just be blindly guided
by politicians or pressure groups...

Anyway, as luck would have it, about 3 years ago I met a
very talented artist, Paul Fryer www.paulfryer.net
. We hit it off straight away, and have since been working on a number of
artistic pieces which bridge the gap between science and art. I'm enjoying
the collaboration hugely, but am also hopeful that the resonance and
visceral response which art can generate will inspire a wider audience to
learn more about science.

The launch of our first big piece will be in mid-April and
I'll hopefully find time to provide details of some of the underlying
science after that. In the meantime, I'll just say that we've found
something much more interesting to do with the power required to boil a
kettle!

Colin.

(I was struck while writing the above text by the
contrast with the earlier material which I've left below. I think
the best explanation is that the new material is trying to put over some
serious thoughts to a broad audience, whereas the older material is just
casual chat on a recreational subject to fellow techies C.)

Update (16 August 2003)

Lots going on, but not much Tesla related. My
current top project is an evolution of the BatBlaster
audio slalom device for vision impaired water skiers. It's provisionally
called the LazerBlazer and the system outline can be found here
(~500K PDF doc with hi-definition photos) or here
(~100K PDF docs with lo-definition photos for faster loading).

Update (8 September 2001)

I've recently got a 3KVA mini-pig + ballast so larger
sparks are on the way. I'm also working on an MW54 jet engine and a
Stirling engine powered by the heat of your hand.

The later is particularly pleasing and I would
thoroughly recommend looking at the engines on the Exergia website http://www.exergia.de

Update (28 May 2001)

Had a great day at Corby. I'll update this page
properly later, but for now here are some pics: Pictures from Corby 2001

Update (29 October 2000)

I ran the coil at full power last night at the Winter
Teslathon in Cambridge. After slight retuning to allow for the lack
of a garage ceiling I was consistently getting 37" strikes to the
building wall!

Now all I need is that spun toroid...

Update (13 October 2000)

Lots has happened since my last update.

I've built a new MMC using a modular design and RS
rather than LRC capacitors.

My RSG has been upgraded to have a thicker disk,
larger electrodes and a more powerful motor.

The strobe circuit has been tweaked to give a more
solid lock.

I've clipped the leads connecting the MOVs into my
NST filter circuit, as it turned out that I hadn't rated them
correctly and they were stopping resonant charging of my tank
capacitor.

I've temporarily increased the topload size by
stacking another ducting toroid on top (I've got a spun
aluminium toroid on order).

My control box is finished including safety
interlocks.

Using experimentation and the PSpice schematics on
Richie Burnett's site I've phased my RSG for optimum spark length.

Taken together these improvements now mean that I can
get good solid 24" discharges, but still only at 75% on the variac!

For now I've just updated the strobe schematic and
included a new section listing some of my favourite Tesla coil links, but
I should hopefully soon have some pictures of the new components and the
coil in operation.

Update (14 July 2000)

I've now included details of the zero-crossing strobe
I'm using for adjustment of my RSG.

Update (3rd July 2000)

I've just fired my coil up for the first time tonight
and it worked like a treat!

With nothing more than rough scope tuning, and no
adjustment of the spark gap phase I got 16" to an earthed target when
at 65% on the variac. I daren't currently go any higher as the arcs
are bound to hit the low ceiling and thence the house wiring.

There's obviously a lot of tweaking to do in terms of primary tap point
and gap phase, but I'm frankly quite pleased with 16" for a first
effort. I was particularly pleased with the rotary gap, which lit at
only 10-15% on the variac, and gave nice controllable output from small
1" purple corona to 16" white hot arcs.

C.

My first serious Tesla coil, at Corby 2001.

Basic parameters

15 turn 8mm copper pipe primary (designed to tap at 10 turns)

5" x 23" secondary wound with 0.5mm wire

12" x 5" top-load made from dryer duct

14nF 10KVrms MMC (hanging below the center of the coil)

200bps Sync RSG made from a grinder

10KV 50mA NST

RC + MOV protection circuit

Construction Details

(Pictures are thumbnails.)

The primary is supported by 9 bars made from cable conduit. The
holes were drilled with the aid of a jig made using conduit clips and a
nail to index one hole off the next.

Heavy duty cable from an old UPS is attached to the primary using a
modified fuse holder.

The close-up also shows the cable conduit supports, and their
attachment to the base using PCB standoffs.

The topload is 5" aluminium dryer duct formed round two 7"
pie tins. The two ends of the duct were attached to each other by
stitching with cotton thread.

The stand-off (like the base legs) are made from PVC pipe fittings.

The secondary coil was wound on a PVC form intended to be used in a
ventilation system.

The wire was placed at 48 T.P.I. with the aid of the
lathe's screw cutting gearbox.

It was given multiple coats of polyurethane
varnish, each being allowed to dry with the form rotating. This gave a
very smooth and even finished.

The top of the secondary is finished with an HDPE disk made from a
cutting board, turned up and epoxied in place.

Glued to the centre
is the cap from a waste pipe access port. This provides an easy
means of attaching the top-load standoff.

The strike-rail is also 8mm copper pipe, flattened and attached to the
supports using bolts.

Two views of the MMC tank capacitor. It is made from three
strings of 9 x 0.047uF 1500V poly capacitors from LCR.

The
capacitors are mounted on both sides of a small HDPE cutting board with
10Meg bleed resistors to limit the time the capacitor will hold a
dangerous charge.

My 3000RPM 200 bps synchronous RSG, made using a small bench grinder
from B&Q.

The stationary electrodes are made from M6 brass machine screws, screwed
through tapped brass bars, which in turn are bolted to Tufnol supports.

The disk is made from G10 PCB, with 4 flying electrodes made from M4
brass machine screws.

The electrodes are connected using copper track left on the back of the
disk.

The motor was made synchronous by machining two flats on the rotor.

To get a good lock the flats needed to be 20mm wide.

(Note the rotor bars showing through the laminations of the core.)

To get the disk to run true the grinding wheel washers needed to be
trued up.

The NST protection filter combines an RC filter with MOVs to clamp the
voltage across the transformer.

The
Colchester Bantam lathe which made the making of the coil much easier than
might otherwise have been the case.

(Note, the screwcutting gearbox is
currently removed for refurbishment.)

To help adjust my RSG, I've adapted a simple kit from
Maplin to provide a 50Hz strobe synchronized to the zero-crossing of
the mains.